code: def test_onset_detect_nosignal():
      librosa.onset.onset_detect(y=None, onset_envelope=None)
  
imports: import pytest
  from contextlib import nullcontext
  import os
  import warnings
  import numpy
  import librosa
  from test_core import srand
label_desc: Use image node_id 14 for calling a global function with example usage: test_onset_detect_nosignal() without return types